BDC (Bullet Drop Compensator)
Definition
Elevation turret or reticle markings that encode the required elevation correction for a specific load at preset ranges. Allows rapid correction without mental calculation. Load-specific: calibrating for one ammunition type does not apply to another.
- Function
- Encodes elevation correction for preset ranges
- Location
- Turret markings or reticle stadia lines
- Load dependency
- Specific to one ammunition ballistic profile
- Benefit
- Removes need for mental ballistic calculation in the field
Common questions
Why can a BDC turret give a wrong correction?+
The markings are calibrated for one bullet weight, velocity, and ballistic coefficient. Swapping ammunition, or shooting at a different altitude or temperature than the calibration conditions, shifts the true drop away from the marked values.
How is BDC relevant to a shooting reconstruction?+
If a recovered rifle has a BDC reticle or turret matched to a specific load, that supports an inference about the shooter's intended engagement range and the ammunition the case is built around, useful when correlating scope settings with trajectory analysis.
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